A Computed Tomography (CT) scanning apparatus usually comprises a gantry and an x-ray generator capable of emitting X-rays to a target object (e.g. a user to be scanned) for scanning while rotating. The gantry comprises the X-ray generator fixed thereon. Hence, the X-ray generator will rotate as the gantry rotates, and emit X-rays to the target object at the same time, so as to scan each site of the target object to be scanned. The gantry further comprises an imaging device for receiving X-rays (including the X-rays penetrating through the target object) emitted from the X-ray generator. The imaging device converts the received X-rays into electric signals, and sends such electric signals to a console of the CT apparatus. The console of the CT apparatus comprises receiving and processing the electric signals sent by the imaging device so as to obtain a scanning image of the target object including an image of each site of the target object to be scanned. In addition, the console further comprises a display for displaying the scanning image.
The CT apparatus further comprises a gantry rotation control device for controlling movement of the gantry. The existing gantry rotation control device controls the gantry to rotate at a uniform speed. However, when the rating X-ray emitting capacity (generally represented by mA values) of the X-ray generator of the CT apparatus is relatively small and/or the sizes of some sites of the target object to be scanned are relatively big, a scanning imaging with an expected image signal to noise ratio may not be obtained; or, when the rating X-ray emitting capacity of the X-ray generator of the CT apparatus is relatively big and/or the sizes of some sites of the target object to be scanned are relatively small, X-rays with excessive radiation doses may be radiated to these relatively small-sized sites of the target object to be scanned.
Hence, here is expected a CT apparatus for controlling rotation of a gantry at a varied velocity.